A plasma system includes one or more radio frequency (RF) generators, an impedance matching network, and a plasma chamber. The plasma chamber includes an electrode at a top portion of the plasma chamber and another electrode at a bottom portion of the plasma chamber. The electrode at the top portion has multiple gas inlets for allowing passage of a gas into the plasma chamber.
A wafer is placed on top of the electrode at the bottom portion for processing the wafer. The one or more RF generators are turned on to supply RF signals, which are transferred via the impedance matching network to the plasma chamber. In addition, the gas is supplied via the gas inlets to the plasma chamber. The gas is ignited by the RF signals to generate plasma within the plasma chamber and the plasma is used to process the wafer. During processing the wafer, a variety of controls are implemented to control processing of the wafer.
It is in this context that embodiments described in the present disclosure arise.